The invention concerns a radar system having a radar sensor which comprises a transmitting module, a receiving module and a trigger switch, wherein the transmitting module comprises a first plurality of partial antennas, and the receiving module comprises a second plurality of partial antennas, and wherein, in a first operating mode, the trigger switch operates at least one partial antenna of the transmitting module together with at least one partial antenna of the receiving module to obtain a first, low angular resolution, and wherein, in a second operating mode, the trigger switch operates one group of partial antennas of the transmitting module together with a group of partial antennas of the receiving module to obtain a second, high angular resolution.
The invention also concerns a method for operating such a radar system.
A radar system and a method of this type are disclosed in EP 1 324 068 A2.
Radar sensors are generally used in automotive vehicles to monitor the surroundings of the vehicle for use as e.g. a parking aid, dead angle monitoring, accident anticipation (pre-crash sensing), start/stop operation or drive operation with distance control and/or regulation (cruise control support). The requirements for the angular resolution thereby differ from application to application.
Dead angle near-field monitoring (blind-spot-detection) requires a wide radiation field. Good angular resolution is less important. For maneuvering an automotive vehicle it is e.g. important to know whether an object is located at a blind spot, in which case an immediate stop is required. In contrast thereto, it is less important to know the exact location of the object, since the vehicle must be stopped in any event.
On the other hand, for distance control along a lane, distance information must not be disturbed by vehicles in neighboring lanes. This requires higher angular resolution. To be able to cover various angular resolution requirements with one single radar sensor, the angular resolution should be switchable or controllable.
Towards this end, in accordance with EP 1 324 068 A2, finger-like mutually engaging partial antennas of a transmitting module and a receiving module are operated either as individual pairs of transmitting partial antenna and receiving partial antenna or as groups (sets) of neighboring partial antennas. The two different operation modes thereby have two different azimuthal angular resolutions. Each partial antenna of EP 1 324 068 A2 is connected to a trigger switch via an independent separate switch. The plurality of switches and associated control paths requires a relatively large area in such an arrangement. This is true, in particular, in view of the limited number of operating modes which differentiate only between a high azimuthal resolution and a low azimuthal resolution.
In view of this prior art, it is the underlying purpose of the invention to provide a radar system with switchable angular resolution which permits a plurality of operating modes and which has minimum area and minimum switching requirements.